1. Field of the Invention
The invention relates to the use of succinate dehydrogenase SDH inhibitors (SDHIs), in particular bixafen, penflufen or fluopyram for controlling wood diseases in grape, to a method for treating plants or plant parts for controlling wood diseases in grape and to a method for controlling wood diseases in grape plants and plant parts, in particular roots and in plants which grow from the seedlings, grafts and cuttings, by treating them with SDHIs.
2. Description of Related Art
Wood diseases includes a complex of diseases provoked by the presence of fungal species including Acremonium spp., Botryosphaeria spp, Botryosphaeria obtuse, Botryosphaeria dothidea, Cephalosporium spp., Eutypa lata, Formitiporia mediteranea, Phaemoniella chlamydospora, Phaeoacremonium aleophilum, Phialophora spp., Phomopsis viticola. Phomopsis viticola is responsible for the disease excoriosis, Eutypa lata for the disease Eutypa, Botryosphaeria spp are responsible for Black dead arm disease. Esca is a disease which is caused by at least three fungal species including Phaeomoniella chlamydospora, Phaeoacremonium aleophilum, and Fomitiporia mediterranea. These pathogens were localized in the woody tissues of perennial organs and in lesser proportions in annual canes but never in leaves where symptoms express. The epidemiology is also specific because two forms of symptoms may be distinguished. Chronic symptoms consist of light-green and chlorotic, irregular areas between the veins or along the leaf margin, which gradually spread from the basal to the distal part of the shoot, whereas a more severe form, so-called apoplexy, corresponds to a sudden leaf wilting that leads to death of canes or the whole plant within a few days (Larignon et al, Comptes endus Biologies (2009), 332 (9), pp 765-783). Due to the suddenness of the latter, the causes of the apoplectic form of wood diseases are difficult to investigate and, therefore, less documented. However, the speed of visible symptom development suggests that apoplexy results from early events affecting plant physiology linked to the presence of esca fungi in the wood (P. Letousey et al, Phytopathology (2010), Vol 100 (5), pp 424). Several fungicides and application methods have been described for treating Esca, for example fosetyl-aluminium, penconazole, cyproconazole, tetraconazole (Di Marco et al., Phytopathol. Mediterr, (2000) 39, 232-240). Fluopyram in combination with tebuconazole (Tradename Luna Experience) against Eutypa lata is not recommended by the University of California (J Adaskaveg, Report Efficacy and timing of fungicides, bactericides and biologicals for deciduous tree fruit, nut, strawberry, and vine crops (2011)). Wood diseases are difficult to treat as the fungus grows in the woody parts of plant and is therefore not easily accessible for the fungicide. Also systemic fungicides are only of limited use as in most cases they are not evenly distributed throughout the plant. Therefore currently protective treatments, in particular of wounds serving as the entry point for the fungi, are recommended (M Fischer, Der badische Winzer, October 2007, pp 17-19). Consequently there is a need for more efficient treatment of wood diseases in grape.